As logic integrated circuits (ICs) have migrated to lower working voltages in the search for lower power consumption and higher operating frequencies, and as overall system sizes have continued to decrease, IC power supply designs with smaller size and higher efficiency are in demand. Switch mode power supplies, or DC to DC converters, as they are sometimes called, are frequently used to supply IC circuits such as digital signal processors (DSPs) and mixed signal analog circuits, etc., to efficiently convert an input supply voltage to voltage levels appropriate for internal circuitry as well as external circuitry that the IC is coupled to. For instance, a 5.0 volt supply voltage provided to a BiCMOS IC may need to be decreased internally to 2.8 volts to operate internal CMOS circuitry. As appliances and circuit designs continue to decrease in size, the need for smaller and more efficient IC switch mode power converters increases.
DC to DC converters, as part of the regulated power supplies, are commonly used to provide low ripple and tolerance supplying voltages to electronic systems. Most electronic systems for computer, communication and industrial applications typically include integrated circuits like microprocessors, digital signal processors, memory, for example, which tend to cause high slew rate transients in the entire electronic system. A trend exists in the industry towards lower supply voltages for electronic systems, while the required current from power supply systems is increasing. Optimal control approaches on DC to DC converters are very important to meet tight static and dynamic tolerance requirements while supplying voltages at minimum costs.